• Title/Summary/Keyword: 수화수축

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생쥐의 자궁내막에서 발정주기에 따른 aquaporin 4, 5, 8의 발현양상과 존재부위

  • 이지원;계명찬;강수만;이성은;강한승;김문규
    • Proceedings of the Korean Society of Developmental Biology Conference
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    • 2003.10a
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    • pp.61-61
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    • 2003
  • Aquaporins (AQPs)는 다양한 상피세포와 내피세포에 존재하며 다량의 물 수송을 촉진하는 막성단백질로 현재 11개의 AQP가 (AQP0-10) 발견되었으나, 아직 생리적, 기능적 분석은 불충분한 상태이다. 생쥐의 자궁내막은 발정주기 동안 호르몬의 자극에 따라 부풀어오르거나 수축하는 변화를 보이며 에스트로젠과 몇몇 혈관에 작용하는 매개체에 의해 자궁 혈관의 투수성이 증가한다는 보고는 있으나, 자궁액의 수송 메커니즘에 대해서는 뚜렷하게 밝혀진 바가 없다. 발정기의 생쥐 자궁은 자궁내막세포의 증식과 함께 수화되는 특징을 보이며 자궁내강으로 물이 수송되어 luminal fluid의 점성이 낮아지는 현상이 나타나는데, 이 때 AQP가 water channel로서 중요한 역할을 할 것으로 보고 본 실험에서는 면역조직화학법(immunohistochemistry)과 역전사중합효소연쇄반응(Reverse-transcriptase polymerase chain reaction)을 통해 발정기 자궁의 수화와 AQP 발현의 상관성에 대해 알아보고자 하였다. 면역조직화학법의 결과 발정주기의 다른 시기에 비해 발정기(estrus phase)에 자궁상피세포에 AQP4, 5, 8 protein이 다량 존재하는 것으로 밝혀졌고, 근육층(myometrium)에서의 발현은 발정주기 동안 차이가 없었다. Whole uterus로 RT-PCR을 수행한 결과 AQP4, 5, 8 mRNA는 luteal phase에 비해 follicular phase에 더 많이 발현하는 것으로 확인되었다. 또한 LCM(Laser Capture Microdissection) system을 이용하여 luminal epithelium과 stromal cell을 분리하여 RT-PCR을 수행한 결과 AQP4, 5, 8 mRNA는 stromal cell 보다는 luminal epithelium에 더 많이 발현하며, 이 역시 follicular phase에 발현량이 증가함을 확인하였다. 이러한 결과로 미루어 생쥐 자궁에서 AQP4, 5, 8은 발정주기 내막에 발현이 증가하며 이는 자궁내강 안으로 수분을 수송하는데 주요한 기작으로 사료되며 estrogen에 의한 조절 가능성을 암시한다.

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The Effect of Replacement Ratio of Mineral Admixtures and Curing Condition on Compressive Strength of Hot Weather Concrete (혼화재 치환율 및 양생조건이 서중콘크리트의 압축강도에 미치는 영향)

  • Kong, Tae-Woong;Lee, Soo-Hyung;Jang, Jae-Hwan;Lee, Han-Baek
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.629-632
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    • 2008
  • As concrete is a material which is subject to wide quality fluctuations by temperature, grip of seasonal feature and maintenance of ambient temperature and humidity to secure the quality required after casting concrete are able to keep away from harmful effects. In case of summer, a high temperature has caused rapid hydration reaction of cement in early age, which has caused to decrease strength by autogenous shrinkage. Therefore we need to consider a countermeasure for decrease in the hydration heat of hot-weather concrete, according to minimize water and cement content and use mineral admixtures In this experimental research, the compressive strength development for replacement ratio of mineral admixtures, curing temperature and methods of concrete was investigated to confirm the effects of mixture design and curing condition on compressive strength of concrete.

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An Experimental Study on the Properties of UHPC with Different Types of Cements (시멘트 종류에 따른 초고성능 콘크리트의 특성에 관한 실험적 연구)

  • Park, Jung-Jun;Kang, Su-Tae;Ryu, Gum-Sung;Koh, Gyung-Taek;Kim, Sung-Wook;Lee, Jang-Hwa
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.345-348
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    • 2008
  • A Cement account for the most amount than other materials in the material composition of ultra-high-performance concrete. If we especially consider the effect of high temperature curing on the cement hydration and the problems of autogenous shrinkage, heat of hydration we need selection of proper cement type by grasping influence of cement in the properties of UHPC. Therefore, in this paper we examined properties of fluidity, compressive strength and elastic modulus of UHPC due to domestic portland cement types. In results, we could get a result that the low heat cement increase fluidity, compressive strength in UHPC compare with high early strength cement and ordinary portland cement. we are systematically going to examination on the influence of UHPC by domestic portland cement types.

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Long-term Durability Characteristics of Fly ash Concrete Containing Lightly Burnt MgO Powder (저온 소성한 MgO 분말을 함유한 플라이애시 콘크리트의 장기재령에서의 내구특성)

  • Jang, Bong-Seok;Choi, Seul-Woo;Lee, Kwang-Myong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.3
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    • pp.909-916
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    • 2013
  • Concrete containing lightly burnt MgO has long term expansibility. It also could compensate for the thermal shrinkage of mass concrete, because the hydration of MgO proceeds at a slow pace to long-term age. Thus, lightly burnt MgO has been applied to the construction of mass concrete such as dams. Recently, the expansion characteristics of MgO concrete with fly ash that could be applied to mass concrete for the reduction of hydration heat have been studied and however, limited studies on its durability. This study investigates the long-term durability characteristics of fly ash concrete with lightly burnt MgO. The durability tests on carbonation, freezing-thawing, diffusion of chloride, and resistance to sulfate attack were carried out for MgO concrete with curing for 360 days in submerged condition with different temperature of 20 and $50^{\circ}C$. The results reveal that MgO concrete shows a greater resistance of carbonation, diffusion of chloride, and resistance to sulfate attack. On the other hand the resistance of freezing-thawing was little influenced by MgO powder.

A Study on the Evaluation of Thermal Stress of Massive Concrete Structure (매스콘크리트구조물의 온도응력평가에 관한 연구)

  • 강석화;정철헌;정한중;이용호;박칠림
    • Magazine of the Korea Concrete Institute
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    • v.7 no.2
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    • pp.126-135
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    • 1995
  • Thermal cracks are occured when thermal stress due to the hydration of cement exceeds the tens~le strength of concrete. Since crackmg causes poor durability of concrete, the effect of ther ma1 cracking should be includod for the design and construction of massive concrete structures. In this study, an experiment is performed for the investigation of time dependent thermal stress history. In order to evaluate thermal stress. two methods are employed. One 1s the evaluation method of thermal stress based on the measurement from embedment stram gauge with non-stress strain gauge and the other 1s based on the measurement from concrete stress gauge. As a result of this study, the value corrected by the former shows good agreement with the latter. The validity of the proposed method for the evaluation of thermal stress 1s explored.

A Evaluation on the Field Application of High Strength Concrete for CFT Column (고강도 CFT용 콘크리트의 현장적용성 평가 및 장기거동 예측)

  • Park, Je Young;Chung, Kyung Soo;Kim, Woo Jae;Lee, Jong In;Kim, Yong Min
    • Journal of the Korea Concrete Institute
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    • v.26 no.6
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    • pp.707-714
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    • 2014
  • CFT (Concrete-Filled Tube) is a type of steel column comprised of steel tube and concrete. Steel tube holds concrete and the concrete inside tube takes charge of compressive load. This study presents structural performance of the CFT column which has 73~100 MPa high strength concrete inside. Fluidity, mechanical compression, pump pressure test in flexible pipe were conducted for understanding properties of the high strength concrete. Material properties were achieved by various experimental tests, such as slump, slump flow, air content, U-box, O-Lot, L-flow. In addition, mock-up tests were conducted to monitor concrete filling, hydration heat, compressive strength. From construction sites in Sang-am dong and University of Seo-kang, long-term behaviors could be effectively predicted in terms of ACI 209 material model considering elastic deformation, shrinkage and creep.

Mechanical Properties of PHC Pile Concrete using Alpha-type Hemihydrate Gypsum (알파형 반수석고를 활용한 PHC 파일 콘크리트의 역학적 특성)

  • Hong-Seop Kim;Kyoung-Su Shin;Do-Gyeum Kim
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.12 no.1
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    • pp.25-32
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    • 2024
  • In this study, the mechanical properties of PHC pile concrete using alpha-type hemihydrate gypsum were evaluated. As the replacement ratio of alpha-type hemihydrate gypsum increased, the setting time rapidly accelerated. In particular, when replacement ratio exceeded 20 %, the setting time was shortened due to rapid hydration reaction, making it impossible to secure working time. As the replacement ratio of alpha-type hemihydrate gypsum increased, the ettringite and gypsum peaks tended to increase, and it is believed that the shrinkage of concrete decreased due to the increase in the ettringite peak. At a As the replacement ratio of 5 to 15 % for alpha-type hemihydrate gypsum, the compressive strength increased or was found to be equivalent to that of OPC. But at 20 % substitution, workability deteriorated due to rapid setting, so use of the 5 to 15 % range is considered appropriate.

Fundamental Properties of Fly ash Concrete Containing Lightly Burnt MgO Powder (저온 소성한 MgO 분말을 함유한 플라이애시 콘크리트의 기본 물성)

  • Choi, Seul-Woo;Jang, Bong-Seok;Lee, Kwang-Myong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.2
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    • pp.475-481
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    • 2013
  • Although the lightly burnt MgO at $850{\sim}1000^{\circ}C$ has expansibility, it does not lead to unsound concrete. The expansion of MgO could compensate for shrinkage of concrete for a long-term, because the hydration of MgO occurs at a slow pace. Recently, the study and application of mineral admixture such as fly ash and blast furnace slag have increased for the hydration heat reduction, durability improvement, and reducing $CO_2$ emission in the construction industry. Thus, it is necessary to research on the concrete that contains both a mineral admixture and MgO as an expansion agent. This study investigates fundamental properties of fly ash concrete with lightly burnt MgO through various experiments. The adiabatic temperature test results showed that the fly ash concrete with MgO of the 5% replacement ratio had the slower pace of the temperature rise and the lower final temperature than the fly ash concrete. The influences of MgO on long-term compressive strength varied depending on water-binder ratio, and the long-term length change test results indicated the expansion effects of the FA concrete containing MgO.

A Study on the Hydration Ratio and Autogenous Shrinkage of Low Water/cement Ratio Paste (저물시멘트비 페이스트의 시멘트수화율 및 자기수축에 관한 연구)

  • Hyeon, Cheol
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.10a
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    • pp.385-390
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    • 2002
  • Autogenous shrinkage of concrete has been defined as decrease in volume due to hydration cement, not due to other causes such as evaporation, temperature change and external load and so on. For ordinary concretes, autogenous shrinkage is so little compared to the other deformations that it has been dignored. It has recently been proved, however, that autogenous shrinkage considerably increase with decrease in water to cement ratio. And it has been reported that cracking can be caused by autogenous shrinkage, when high- strength concretes were used. In this study, we propose an analytical system to represent autogenous shrinkage in cement paste in order to control crack due to autogenous shrinkage. The system is composed with the hydration model and pore structure model. Contrary to the usual assumption of uniform properties in the hydration progress, the hydration model to refine Tomosawa's represents the situation that inner and outer products are made in cement paste. The pore structure model is based upon the physical phenomenon of ion diffusion in cement paste and chemical phenomenon of hydration in cement particle. The proposed model can predict the pore volume ratio and the pore structure in cement paste under variable environmental conditions satisfactorily The autogenous shrinkage prdiction system with regard to pore structure development and hydration at early ages for different mix-proportions shows a reasonable agreement with the experimental data.

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Hydration of Expansive Materials with CSA-System (CSA계 팽창재료의 수화특성)

  • 정성철;송명신;이경희;한천구
    • Journal of the Korea Concrete Institute
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    • v.14 no.5
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    • pp.631-637
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    • 2002
  • This paper deals with hydration properties of the OPC with CSA-system expansive materials. In OPC using CSA, that was formed monosulfate for the main part. but In OPCs using CSA and gypsum, using CSA and gypsum and lime, that were formed ettringite for the main part. On the shrinkage ratio, the former is larger than the latter And CSA-system with gypsum and lime is smallest of all systems. According to dimension of shrinkage ratios are as follows; OPC using CSA only> OPC only> OPC using CSA and gypsum> OPC using CSA, gypsum and lime. And "R"s are 0.32, 0.37, 0.8, 0.8, 0.8 each others. In OPC with CSA-system expansive materials, we know that expansive properties were depend upon the value of "R". "R" means supplying quantities about demanding quantities for ettringite. In the case of expansive materials with CSA-system and lime, it is to be rich Ca(OH)$_2$ in the solution. so, it is formed small ettringite as the needle shapes. they are contribute to expansive.